Proponents of the new law argue that a ban is intended to create a “level playing field.” Opponents say that the policy is discriminatory and unnecessary.

Idaho this week became the first state to officially ban transgender athletes from competing on women’s sports teams, with Gov. Brad Little signing a law defining "athletic teams or sports designated for females, women, or girls” as only open to cisgender girls.

The new law applies to competitive, intramural, and club teams at public schools and colleges, as well as teams at private schools that compete as part of the Idaho High School Activities Association and the National Collegiate Athletic Association. The policy only applies to transgender female athletes. Any “dispute” about an athlete’s gender now would be resolved by a physician’s examination of the student’s internal and external reproductive anatomy, testosterone levels, and genetic makeup.

The new law, along with another law signed the same day that prohibits transgender people from changing their birth certificates, faced immediate backlash from LBTQ organizations—not only for the content of the policies, but for their timing. Little signed the bills into law the day before the Transgender Day of Visibility, an annual international initiative to raise awareness of the discrimination that transgender people face.

Rodrigo Heng-Lehtinen, the deputy director for the National Center for Transgender Equality, chastized Little for taking time to focus on these particular bills during the coronavirus pandemic. “Our country is facing an unprecedented health crisis, and Gov. Little and members of the Idaho Legislature have prioritized attacking transgender student athletes with this discriminatory and unnecessary new law,” Heng-Lehtinen said in a statement. “With so much suffering right now, Idaho is making sure trans kids suffer more.”

Similar bills have been introduced in at least 16 other states during the 2020 legislative session, but no other ones have at this point become law. In states where legislative action seems unlikely, conservative legal groups are leading the charge. Kristen Waggoner of the Alliance Defending Freedom, the organization behind a lawsuit challenging a Connecticut policy that allows athletes to compete in the division in line with their gender identity, said Idaho’s law will “level the playing field” for cisgender female athletes. “When the law ignores biological differences, women and girls bear the brunt of the harm,” she said. “Female athletes lose medals, podium spots, public recognition, and opportunities to compete.”

Many challengers of athletic policies that allow transgender girls to compete with cisgender girls argue that being transgender gives competitors an unfair physical advantage because their testosterone levels may give them increased muscle mass—but scientific research on that conclusion isn’t definitive.

The law in Idaho relies on a study of 11 transgender women that found they retained an advantage in muscle mass and strength after 12 months of hormone therapy. However, the transgender women in the study ranged in age from 23 to 31, meaning most of them were older than public school or college-aged athletes—and their results are likely different from transgender athletes who undergo hormone therapy before or during puberty. The study’s authors also admit that this study “only examined a few selected performance markers and the participants were untrained,” meaning it “is still uncertain how the findings would translate to transgender athletes undergoing advanced training regimens during the gender-affirming intervention.”

Some health researchers, including M. Gregg Bloche, the co-director of the Georgetown-Johns Hopkins Joint Program in Law and Public Health, dispute assertions that banning transgender girls from sports is a decision rooted in science at all. “There are lots and lots of causes for differences in performance during sporting events or other enterprises where accomplishments are compared,” said Bloche. “Some of them we remedy and some of them we don’t.”

Bloche pointed to golf handicaps that allow players of different skill levels to play competitively as one example of a treatment for an advantage, and to the allowance of extra time during standardized tests for students diagnosed with attention deficit disorder. But other differences we simply accept, he said. Baseball teams don’t, for example, move the fence further infield for smaller players who hit fewer home runs. “We make judgements about when differences are ‘unfair’ and should be adjusted to equalize performance, and when they’re simply differences based on any number of factors,” he said. “Whether we accept the outcomes or not is not a scientific question—it’s a social and cultural question.”

The NCAA already requires transgender girls to take medication that suppresses their testosterone levels for at least a year before they are able to compete—a policy that some Idaho athletes say makes the new law completely unnecessary. Lindsay Hecox, a transgender freshman who hoped to compete on the women’s track team at Boise State University, said she already followed all the guidelines set by the NCAA for transgender athletes and would have been eligible in the 2020-2021 season. Now, she said the bill will discourage transgender athletes like her from playing sports altogether. “Supporters of this bill are attempting to fix a problem that was never there,” she said in a statement. “It’s unfair, unnecessary and discriminatory, and it ignores the commitment we’ve made to rigorous training and the importance of athletic competition to our lives.”

The law will almost certainly face a legal challenge in the coming months. The Idaho attorney general’s office released a report to Little and state lawmakers warning that lawyers there “have concerns about the defensibility” of the sports policy, calling it “constitutionally problematic.” The attorney general’s office seemed particularly concerned with the proposed verification method for determining an athlete’s gender, noting that the policy would require students to submit themselves to an “invasive examination and … provide highly intimate information on demand.” Five former Idaho attorneys general also wrote to Little earlier in the month urging him to veto the bill in order to “save the state from having to pay out substantial legal fees” after the state is inevitably sued. “The Attorney General has provided sound advice and fair warning,” they wrote. “Please heed it.”

State Sen. Mary Souza, the Republlican sponsor of the bill, told lawmakers during debate that “there is a third-party group that has been working with us on this bill and it will be responsible for any legal defense fees.” Souza later clarified that the group is Alliance Defending Freedom, but she did not know the details of the payment arrangement.

The American Civil Liberties Union of Idaho has already promised to sue over both the athletic law and the law banning birth certificate gender changes. “The ACLU will see the governor in court,” the group said in a statement. “We encourage all Idahoans to email, call, and tweet Gov. Little to express outrage and disappointment at wasting precious taxpayer resources on blatantly anti-transgender bills at a time when we should be coming together for the health and wellbeing of our people.”